Bodywork Questions

Looking for some advise on how what to do for cleaning up inside car roof and under package tray, general tight areas.
When you see many restorations going beyond factory preparations to paint the inside of cars with body color how fussy are restorers being before applying paint?

I am dealing with mostly light surface rust but want to at least clean it up and apply some protection even though everything is mostly hidden in those areas after assembly.
What are you doing to prep roof? Blasting? Sanding with what? Cleaning metal before paint with what? What paint or rust inhibiting products recommended?


Hoping to do some things myself to save some labor while the car is home....

Thanks

Been wondering that myself for a long time !! Personally I'm thinking of spraying those areas with a rust converter and then something like Rustoleum. Then the overspray of body color should do nicely over the Rustoleum. Once everything's dry I'm thinking I'd spray all the lower seams in the doors and rockers with Rustcheck.

blasting to remove the rust,wax and grease remover,epoxy prime.
i try to avoid converters or encapsulators as much as i can.
i never had any good luck with them.

I'm not keen on "encapsulators" either as they are basically just sealing the rust to the existing surface. But since rust needs moisture to progess, as long as it seals the moisture out it should stop the process.

I like "converters" which are usually removers as well. But complete removal usually involves a complete soak or repeated wetting and scrubbing - not practical in many of the areas of concern here. In fact, blasting only works on easily accessible areas too! The "converters" will get wherever moisture was able to get - down into door seams, etc.. A good wetting will convert the rust and leave a phosphorous coating that can be painted or sprayed with something like Rustcheck.

Keep in mind that if rust is so heavy that a converter isn't practical, it should probably be cut out and replaced. Converters will work great on surface rust that's formed on unpainted surfaces - undersides of the roof, inside doors, inside the quarters, etc..

Best thing is blasting, but even blasting can't get into all the hard to reach areas such as below quarter windows, below pillars, and cavities under the rear seat.

The best solution I know is to spray on or brush on Rust Cure, a phosphoric acid, 2 coats at least one week apart. That's what I do, and so do 2 restoration shops I've talked to. They pour Rust Cure into inaccessible cavities while the car is on a rotisserie so the liquid can slosh around while the car is rotating.

I've been using Rust Cure for decades. Some areas are convenient for brushing it on with a nylon bristle brush (natural bristles will be eaten by the acid). A hand operated spray bottle will cover large areas quickly, but avoid breathing the mist - wear a face mask.

I've coated much of my car with Rust Cure to halt rusting while waiting for body and paint work. Relative humidity here is high, and rusting quickly happens in a closed garage. Two coats of Rust Cure is almost a permanent fix, but not quite here due to humidity. I put 2 coats on outdoor metal gates a few years ago, and they are still mostly rust free. You can test it yourself the same way.

Some pointers about use:

1. Since it is an acid, it reacts with and discolors concrete to white. I don't mind this on my driveway but strive to prevent it inside my garage.
2. It discolors and streaks body paint which usually doesn't matter if repainting anyway. I have put no Rust Cure on the top side of my package tray in case I need a pristine place for color match. Excess or foamy Rust Cure on body panels is easy to remove with a Scotch Brite pad.
3. Wiped-off coatings of Rust Cure are good to paint over. Any sanded or blasted bare metal parts I have that are waiting for primer get 2 wiped-off coats of Rust Cure, and they are ready for priming without any further cleaning or sanding. Wipe off with a paper towel.
4. For body panels and small exposed parts, apply 2 coats and wipe one week apart and wait a week before painting over the Rust Cure. There's no need to wipe off the Rust Cure on floor pans or other hidden and hard to reach places such as the bottom side of the package tray or the tops of wheel tubs.

Home Depot, one gallon of Kleen-Strip Prep & Etch. Go get a horse sprayer (half quart size) these you can adjust nozzle from mist to stream. Mix half water to mix, just spray, dries to a white powder and wash it before taking to painter, rust will be gone. Real heavy rust, wire brush to scratch it up apply more. Anyway directions are on the bottle.

Thank you for the comments so far. I am planning on having The shell blasted with crushed glass. But wanted to avoid doing it on the inside So it's not hard to clean out.
Any other body guys out there to chime in? The more experiences the better.

Car has about 6 paint jobs over the original Q5 paint which I have stripped on the driver side rear quarter

Kleen-Strip Prep & Etch is a phosphoric acid similar to Rust Cure. The above comments about Rust Cure apply to this also, but the concentration of acid in each probably isn't the same. Other similar solutions are Naval Jelly, Ospho, etc.

Prices aren't the same either, but AFAIK Rust Cure is the most acidic and strongest of all similar products.

One other pointer: Don't get phosphoric acid on zinc (or cad) coatings. Other metal coatings like chrome plating will also be damaged.

Another: Rust Cure is extremely acidic, but getting it on your skin has little to no effect. If you feel some itch, wash immediately with soap and water, and you'll be cured. Don't get any on your clothes, or you'll have holes after washing.

Thanks!

I've allways wondered what repeated applications of Evaporust would do. Keep pouring a little into the recesses to keep it wet until the rust is gone. Think it would work?

I would scrub that whole inner cowl area with a rust remover/converter then spray the weld seam with weld through primer and paint the rest with Rustoleum. Before reattaching the outer cowl you might even consider shooting the area under the vents with body color - its not going to get much, if any, during the paint process. Don't forget to mask that area before painting - I'm thinking masking the vents from below and reaching up through the ducts to remove it after painting.

Yes inner cowl will get glass blasting, i am cleaning up around the vent locations with a bit of extra work before blasting. We had to remove it to fix 3 1-inch holes thar were drilled thru inner cowl in the middle for some race plumbing or wiring i guess. What a pain but good opportunity to strip, paint and reassemble as u described....

Ed , make a shallow pool big enough to submerge the roof in and fill it with evaporust and put the car on your rotisserie ...

Let's see, 6 feet wide, probably close to 8 feet long due to the slope of the rear pillars, and at least 8 inches deep because of the curvature of the roof. That's 32 cubic feet of evaporust OR 239 gallons. That's gonna cost !!

Ive had good luck with Rust Mort from 3M. You can spray it in hard to reach places, its an acid and does a nice job of stopping the rust

Ed's loaded , he can afford it ...

Hope you won the lotto! $22 a gallon is tough for me.

i think you can buy it in concentrated bulk..

Rust mort you need to neutralize it after it dries with water to be able to put anything on it. Rut seal is a good product that you can brush on and it will dry rock hard and never have to coat it again. I have put that inside areas that are hard to get anything in like A post areas or inside areas that you can't get say a blaster inside. Is it the best way. No dipping the bodies is but who can really afford that. This is by far the better way than just leaving it. After its all painted I like to spray like 3M Rust Figher I inside the areas to point it runs out of all openings after its sprayed. Best way i have found so far.